Bus queue time estimation of a curbside bus stop is essential to evaluate the operation, reliability and performance of a bus system. Arriving buses and served buses on upstream berths form an overflow queue considering the no overtaking principle and limited overtaking principle. Therefore, the bus dwelling time at the C-th berth may directly influence the stop capacity. The bus queue delay is modeled as a function of bus dwell time at the C-th berth and the dwell time at every berth using different distributions (normal and lognormal distributions) and data fitting approaches. This study aims to estimate the queue time attributed to dwell time at the C-th berth. The results indicate that the queue time should be evaluated by bus dwell time and joint probability density to quantify the negative influence on queue delay. Therefore, in some cases, where decisions must be taken into consideration for more than two buses, the relationship between dwell time at a downstream berth and dwell time at the C-th berth must be considered.